The present invention generally relates to mechanisms that act to support an item while at the same time allowing the item to move across a support surface. In particular, the present invention relates to using a retractable roller mechanism that provides a static support upon the support surface when the item, such as an article of furniture has a relatively high force towards the support surface causing the roller mechanism to retract and when the item has a relatively lower force towards the support surface the roller mechanism automatically separates the static support from the support surface thereby allowing a roller to freely move the item along the support surface.
There has long been a desire to move large, bulky, and unwieldy items easily across a support surface with a minimum of effort while at the same time having the item not be unstable along the support surface during the times when it is desired that the item not to be easily moved across the support surface. This desire to have a roller mechanism or castor mechanism have two position states, being a first or operative position state where the roller serves to allow the item to be easily moved along the support surface and a second or inoperative position state wherein the roller becomes inoperative not allowing the item to be easily moved along the support surface, is well recognized in the prior art.
Previous approaches to this problem have often resulted in complex castor mechanisms that required the item to be lifted in order to actuate the castor into the previously mentioned first or operative position state from the second or inoperative position state or vice versa. The problem with this approach was that it required the item to be lifted, which is unsatisfactory because the desire to avoid lifting the item is the reason for providing roller mechanisms in the first place. Even if a particular item is not all that heavy, the size and bulk of the item usually makes it difficult for a single individual to simultaneously lift the item and operate the roller mechanism to go from the inoperative state to the operative state. In addition most items have multiple roller mechanisms, which require a single individual to lift the item multiple times at different locations. The aforementioned complex caster mechanisms have sometimes included jacks, in which the item can be raised and lowered to effectuate the roller mechanism changing its operating state, however, these mechanisms are still difficult to use for two reasons. First, if the item is located in a confined area or space, the jacking mechanism is difficult to access, and secondly, the location of the jacking mechanism, typically being on the bottom of the item could be difficult for an individual to be able to reach to the jacking mechanism while simultaneously attempting to lift the item. Other approaches to this problem have included using a spherical roller mechanism that fits inside:a mating socket, wherein the socket is retractable into a separate housing to provide both static support on the support surface when the spherical roller and socket assembly are retracted into the housing and when the spherical roller and socket assembly are extended from the housing allowing the item to be moved along the support surface. The problem with the spherical roller is that it operated at a close clearance with the socket assembly and is prone to ingesting foreign material into this close clearance, such as carpet fibers, when the spherical roller was moving across the support surface, which caused a high degree of a frictional resistance to the spherical roller rotating. This resistance to rotation by the spherical roller made it difficult to move the item across the support surface. Another problem with the spherical roller was that it had a small contact area with the support surface which increased the unit loading that the spherical roller placed upon the support surface from the weight of the item, this in turn increased the likelihood of damage to the support surface from the spherical roller and again increased resistance to moving the item across the support surface when the support surface softer such as wood, linoleum, and carpet.
Prior art examples would be U.S. Pat. No. 5,347,680 to Rippe, U.S. Pat. No. 5,001,808 to Chung, and U.S. Pat. No. 4,783,879 to Weaver that utilize mechanisms to manually adjust the roller height to accommodate the aforementioned operative state and inoperative state. Wherein the roller in the operative state allows the item to be moved across the support surface and in the inoperative state the roller is retracted to allow the roller assembly to statically rest upon the support surface. These mechanisms require manual activation to change the roller assembly from either the operative state to the inoperative state or vice versa, with the previously mentioned disadvantages of manual activation being located at the roller assembly adjacent to the support surface.
There remains a need by for a retractable roller mechanism that supports an item while providing the two desired position states of being operative to allow the item to move along a support surface and being inoperative to statically support the item upon the support surface, without the need for an individual to lift the item or operate the mechanism while at the same time being adaptable to varying support surface types, minimizing damage to the support surface, and being a simple to construct.
It is an object of the present invention to provide an improved fixed pivotal retractable roller mechanism that can be operated conveniently by the normal forces that are applied to the item on which the roller mechanism is mounted, without the requirement of an individual having to access the roller mechanism itself.
It is a further object of the present invention to provide a fixed pivotal retractable roller mechanism wherein the roller is automatically retracted into the housing with the fixed pivotal retractable roller mechanism in an inoperative state by a exerting a force that is greater than the normal weight of the item from the item to the support surface, allowing the item to assume a static or stationary position for the period of time in which the force is continuously applied.
Still another object of the present invention is to provide a fixed pivotal retractable roller mechanism wherein the fixed pivotal retractable roller mechanism is automatically placed into an operative state, and permitting free movement of the item along the support surface when the force from the item to the support surface is equal to the normal weight of the item.
Yet another object of the present invention is to provide a fixed pivotal retractable roller mechanism of simple non-castor construction that allows only bidirectional movement of the item while the fixed pivotal retractable roller mechanism is in the operative state.
Still yet another object of the present invention to provide a pivotal retractable castor roller mechanism with an option for castor capabilities on a roller pivot.
It is still yet another object of the present invention to provide a pivotal retractable castor roller mechanism with an option for castor capabilities on a roller pivot that is non retractable.
It is yet still another object of the present invention to provide a pivotal retractable castor roller mechanism with an option for castor capabilities on a roller pivot that is retractable into an inoperative position state from an operative position state and vice versa.
It is another object of the present invention to provide a retractable roller mechanism that while in an operative position state has a roller that is adaptable to varying support surface types.
It is yet another object of the present invention to provide a retractable roller mechanism that while in an operative state or in inoperative state will result in none or minimal damage to the support surface.
It is further yet another object of the present invention to provide a retractable roller mechanism that is constructed of a minimum number of parts for ease of manufacture and lower unit costs.
The first exemplary embodiment of the present invention is a fixed pivotal retractable roller mechanism that statically supports an item upon a support surface in an inoperative state and supports the item to roll along the support surface in an operative state. Broadly, the first exemplary embodiment of the present invention includes a housing having a symmetrically located axis, a swingarm fixed pivot frame that is pivotally engaged with the housing, with the swingarm fixed pivot frame having pivotal movement that is substantially parallel to the housing axis, also the pivotal movement is relative to the housing. The swingarm fixed pivot frame has an inoperative position state wherein the swingarm fixed pivot frame is retracted such that the housing rests on and statically contacts the support surface and an operative position state wherein the swingarm fixed pivot frame is extended from the inoperative position state toward the support surface. Also included is a spring element that is disposed between the housing and the swingarm fixed pivot frame to bias the swingarm fixed pivot frame toward the operative position state. In addition, a roller element is rotatably mounted in the swingarm fixed pivot frame, the roller element disposed to roll along the support surface when the swingarm fixed pivot frame is in the operative position state. The operative position state results in the housing not being in contact with the support surface, the roller element having a rotational axis perpendicular to and substantially adjacent to the housing axis.
The second exemplary embodiment actually includes a version with a spring element and a version without a spring element that provides a solid support; the following describes the spring element version. The present invention is a pivotal retractable castor roller mechanism that statically supports an item upon a support surface in an inoperative state and supports the item to roll along the support surface in an operative state. Broadly, the present invention includes a housing having a centrally located axis, the housing having a circular base portion and a surrounding cylindrical sidewall extending from the circular base portion towards the support surface to define a housing interior, with the cylindrical sidewall having an exterior portion and an interior portion. Also included is a swingarm castor frame slidably engaged to the interior portion of the sidewall, the swingarm castor frame is positioned to be substantially perpendicular to the sidewall in the operative state. The slidable engagement is operable to move circumferentially around the interior portion of sidewall, the swingarm castor frame also has pivotal movement being substantially parallel to the centrally located axis, the pivotal movement being relative to said housing. The swingarm castor frame having an inoperative position state wherein the swingarm castor frame is retracted such that the housing rests on and statically contacts the support surface and an operative position state wherein the swingarm castor frame is extended from the inoperative position state toward the support surface. In addition, a spring element having a first end and a second end, with the first end being slidably adjacent to the circular base and the second end being attached to the swingarm castor frame. The spring element is positioned to be in-between the centrally located axis and the interior portion, with the spring element being operational to bias the swingarm castor frame toward the operative position state. The spring slidably adjacent first end having a coefficient of friction higher than the swingarm castor frame slidable engagement to provide for the dampening of castor movement. Also, a roller element rotatably mounted in the swingarm castor frame, the roller element is disposed to roll along the support surface when the swingarm castor frame is in the operative position state such that the housing is not in contact with the support surface. The roller element has a rotational axis perpendicular to and substantially adjacent to the centrally located axis.